Editing Pneumatosis intestinalis


''The presence of gas within bowel wall. A finding which can be either primary or secondary, and not always related to small bowel ischaemia.''

== Epidemiology ==

* Uncommon
* Usually occurs 30-60yo

== Aetiology ==

=== Primary (15%) ===

** Benign idiopathic condition
** Not associated with any other conditions or symptoms
** Found incidentally

=== Secondary (85%) ===

** COPD
** Immunocompromised state
** Post-transplant
** Leukaemia
** Lymphoma
** Vasculitis
** Collagen vascular disease
** Chemotherapy or corticosteroids
** Inflammatory, obstructive or infectious conditions of the intestine
** Iatrogenic - endoscopy and jejunostomy placement
** Small bowel ischaemia
** Diabetes

== Pathophysiology ==

* Multiple gas-filled cysts in the wall of the GIT 
** Can occur anywhere from oesophagus to rectum
** Most common in jejunum, followed by ileocaecal and colon
* May be located in the subserosa, submucosa, and rarely the muscularis layer
* Vary in size from microscopic to several centimetres
* When it is seen in neonates, is usually associated with necrotising enterocolitis (see topic under 'paeds')
* Gross inspection - cysts resemble cystic lymphangiomas or hydatid cysts
* Theories for pathogenesis
** Mechanical theory
*** Dissecting gas into the wall, from either within lumen (mucosal tears) or serosa (serosal tears)
*** Could explain association with COPD - coughing
** Bacterial theory
*** Could result from gas-forming bacteria gaining access to submucosa through mucosal breaks
*** Doesn't sound likely - these cysts are sterile
** Biochemical theory
*** Luminal bacteria produce excess hydrogen gas through fermentation

== Presentation ==

* Cyst rupture can give rise to pneumoperitoneum
** One of the few causes of sterile pneumoperitoneum - consider in the patient with free air but no peritonism
* Non-specific symptoms
* Ominous sign when associated with peritonitis, mesenteric gas, or portovenous gas - most likely related to small bowel ischaemia
* Primary disease can give rise to diarrhoea, abdominal pain, abdominal distension, nausea, vomiting, weight loss, and mucus in stools
* Complications
** Obstruction
** Volvulus
** Intussusception
** Adhesions following cyst collapse

== Differential ==

* Pseudo-pneumatosis intestinalis - a.k.a. string of beads sign, intra-luminal gas masquerading as intra-luminal gas

== Assessment ==

* History and examination
** Look for underlying aetiology of secondary disease
** Particularly look for risk of ischaemia - grossly distended, peritonitic
* CT
** Look for associated findings of ischaemia - PV gas, etc
** Pneumoperitoneum is not necessarily concerning
* Bloods
** Usually normal in pneumatosis intestinales

== Management ==

* Indications for exploratory laparotomy - any one of the following
** Peritonitis
** Metabolic acidosis
** Lactate >2
** PV gas
* Non-op management for all others
** Antibiotics
** Elemental diet
** Reconsider surgery if deterioration or at around a week

[[Category:Small bowel]]